Laser systems and devices incorporating nonlinear optical crystals therein are presently used in a wide variety of applications. For example, nonlinear optical crystals are often used in converting laser light having a first wavelength to laser light having a second wavelength. Due to the limited lifetime of nonlinear crystals it is often necessary to shift a position of the nonlinear crystal (relative to the incident laser light) to a new position. Conventionally, actuators such as translation stages having motors (e.g., stepper motors, linear motors) are used to shift the position of the crystal.
While the use of conventional actuators has extended the lifetime of some nonlinear optical crystals, a number of shortcomings have been identified. For example, many conventional actuators contain organic and/or inorganic materials which may be outgassed during actuator use or over time. Laser-induced outgassing may contaminate the laser cavity, be deposited on one or more optics in the laser cavity or in an adjacent optical suite, and/or may compromise performance of the laser system.
In response, in some applications the actuators can be placed outside the crystal compartment and/or laser cavity, whereby mechanical feed-throughs allow interface between the actuator and the crystal. While positioning the actuators outside the crystal compartment and/or laser cavity may reduce or eliminate problems associate with laser-induced outgassing a number of shortcomings have been identified with this approach. For example, with time such feed-throughs can leak thereby allowing undesirable organic and/or inorganic materials to pass into the crystal compartment. In addition, these actuators may be used wherein space outside the laser system and/or cavity is extremely limited. As such, positioning an actuator outside the laser system and/or cavity may be difficult if not impossible.
In light of the foregoing, there is an ongoing need for an actuator which permits the controlled movement of an optical crystal positioned thereon while reducing or eliminating outgassing.